BACKGROUND: Change in the prevalence of asthma-like symptoms in
populations of ageing adults is likely to be influenced by
smoking, asthma treatment and atopy. METHODS: The European
Community Respiratory Health Survey collected information on
prevalent asthma-like symptoms from representative samples of
adults aged 20-44 years (29 centres in 13 European countries and
Australia) at baseline and 10 and 20 years later (n=7844). Net
changes in symptom prevalence were determined using generalised
estimating equations (accounting for non-response through
inverse probability weighting), followed by meta-analysis of
centre level estimates. FINDINGS: Over 20 years the prevalence
of 'wheeze' and 'wheeze in the absence of a cold' decreased
(-2.4%, 95% CI -3.5 to -1.3%; -1.5%, 95% CI -2.4 to -0.6%,
respectively) but the prevalence of asthma attacks, use of
asthma medication and hay fever/nasal allergies increased (0.6%,
95% CI 0.1 to 1.11; 3.6%, 95% CI 3.0 to 4.2; 2.7%, 95% CI 1.7 to
3.7). Changes were similar in the first 10 years compared with
the second 10 years, except for hay fever/nasal allergies
(increase seen in the first 10 years only). Decreases in these
wheeze-related symptoms were largely seen in the group who gave
up smoking, and were seen in those who reported hay fever/nasal
allergies at baseline. INTERPRETATION: European adults born
between 1946 and 1970 have, over the last 20 years, experienced
less wheeze, although they were more likely to report asthma
attacks, use of asthma medication and hay fever. Decrease in
wheeze is largely attributable to smoking cessation, rather than
improved treatment of asthma. It may also be influenced by
reductions in atopy with ageing.